Size Never Affected the Giant Pterosaur Flights

The pterosaurs are back in the air. There are many researchers who doubted the flying ability of the ancient giant winged pterosaur Quetzalcoatlus. But this huge animal weighing around 155 pounds never considered size as a barrier. Counted as the largest flier of all times with a 34-foot wingspan and five foot long skull, the pterosaur Quetzalcoatlus has astounded researchers with its ability to be airborne.

There are several paleontologists who are still trying to piece together how Quetzalcoatlus lived. But Sankar Chatterjee, Horn Professor of Geosciences and curator of paleontology at the Museum of Texas Tech University, has done an analysis to describe the flight dynamics of this animal.

The secret and intricate details of the flight of the massive pterosaur were unveiled by Chatterjee and his colleagues with the help of computer simulation.

"This animal probably flew like an albatross or a frigate bird in that it could soar and glide very well," Chatterjee said. "It spent most of its time in the air. But when it comes to takeoff and landing, they're so awkward that they had to run. If it were taking off from a cliff, then it was OK. But if Quetzalcoatlus were on the ground, it probably had to find a sloping area like a river bank, and then run quickly on four feet, then two to pick up enough power to get into the air. It needed an area to taxi."

According to Chatterjee, there are certain speculations on what this animal looked like. There are several different estimates given by different paleontologist stating that the Quetzalcoatlus could have weighed up to 550 pounds and could have used its forelimbs to play the role of a catapult similar to that of a common vampire bat.

Whereas Chatterjee stated that the computer modeling proved what is possible for a tiny, lightweight, 1-ounce bat is actually impossible for an animal that is 10,000 times heavier. He also stated that the body weight does affect the flight performance. Power drops with body size. Beyond a certain size, it is not possible to flap with the available power. Flight gets difficult. Plus the animal would not be able to maintain height when flying at its maximum power speed and exert full power.

"Its enormous wings must have been difficult to manage," Chatterjee said. "Each wing had at least a 16-foot span, so during its full downstroke it would smash its wing resulting in crash landing. A standing takeoff of flying of such a heavy animal violates the laws of physics."

Chatterjee said that, similar to the present-day condors and other large birds, Quetzalcoatlus probably relied on updraft to remain in the air. He noticed that this giant bird that glides at an angle close to two degrees and a cruising speed of 36 miles per hour had bones that were entirely hollow, filled with air, lightweight and strong. This is how such a large animal could weigh so little and still grow to its enormous size.

The Quetzalcoatlus took off in open airspace by exploiting thermals or wind gradients above the ocean surface.

"Sooner or later the animal would come to the ground, especially during foraging and nesting," Chatterjee said. "Like albatrosses and the Great Kori bustards, which weigh 20 to 40 pounds, ground takeoff was agonizing and embarrassing for Quetzalcoatlus. With a slight headwind and as little as a 10-degree downhill slope, an adult would be able to take off in a bipedal running start to pick up flying speed, just like a hang glider pilot. Once it got off the ground, the giant pterodactyl entered into thermal and soared like majestic masters of the air."

The details were described on November 7 during the annual meeting of the Geological Society of America in Charlotte, N.C.